The present disclosure is directed towards devices and methods for stimulating nerves. In one application, an approach for more effectively treating post-surgical symptoms is contemplated.
A common side effect of surgery is nausea and vomiting caused by a reaction to the general anesthetic. In fact, nausea, vomiting, and retching after surgical procedures not only cause patient discomfort, but can also prolong time to discharge from ambulatory surgery centers and results in unanticipated hospital admissions. A wide variety of prophylactic antiemetics, including antihistamines (e.g., hydroxyzine, promethazine), butyrophenones (e.g., droperidol), and gastrokinetic agents (e.g., metoclopramide), have been successfully used to reduce the incidence of postoperative nausea and vomiting (PONV). However, many of these antiemetics are associated with undesirable side effects.
According to an article by Tang et al. (The Effect of Timing of Ondansetron Administration on Its Efficacy, Cost-Effectiveness, and Cost-Benefit as a Prophylactic Antiemetic in the Ambulatory Setting; 1998 International Anesthesia Research Society), however, Ondansetron is effective for both the prevention and treatment of PONV without producing significant side effects. The manufacturer recommends that ondansetron be administered before induction of anesthesia when used as a prophylaxis. The recommendation is based on the hypothesis that blockade of receptors in the chemoreceptor trigger zone before the arrival of emetic stimuli associated with anesthesia and surgery provides greater antiemetic efficacy. The Tang et al. study concluded that ondansetron administered immediately before the end of surgery was the most efficacious in preventing postoperative nausea and vomiting, facilitating both early and late recovery.
Acupuncture is an ancient medical art dating back many centuries. Traditionally, points in the human body were reached by piercing the body with fine wires or needles. The needles were then rotated or manipulated about their longitudinal axes, for example by rubbing an exposed end of a needle between a thumb and finger, to stimulate the acupuncture points.
Stimulation of specific acupuncture points has been shown in several studies to have an impact in treating conditions such as nausea and vomiting, postoperative pain, headache, smoking cessation, erectile dysfunction, depression, male fertility, dysmenorrhea, and stomach acid secretion and urinary urgency. At the National Institutes of Health Consensus Conference on Acupuncture in 1997, the efficacy of acupuncture was shown in adult postoperative and chemotherapy nausea and vomiting and in postoperative dental pain, and that there were other situations, such as addiction, stroke rehabilitation, headache, menstrual cramps, tennis elbow, fibromyalgia, myofascial pain, osteoarthritis, low back pain, carpal tunnel syndrome, and asthma. Acupuncture was identified as being useful as an adjunct treatment or an acceptable alternative or be included in a comprehensive management program.
There is a recognized acupuncture point just below the crease of the inside of the wrist that has also been associated with the relief of nausea. This is one location of the median nerve whose stimulation is generally credited with producing this relief of symptoms and has been referred to as the P6 acupuncture point. In recent years, it has been observed that electrical stimulation of this location has produced the same effect (Anesthesiology 2007 December; 107(6): 903-8).
Peripheral nerve stimulators have become to be commonly used during surgery to monitor the effects of medications deployed for monitoring of neuromuscular relaxation. These devices are hand held appliances that provide a broad range of current, stimulation frequency and pattern settings. However, they tend to be costly and also lack the portability needed to attach to a patient's wrist without causing significant inconvenience. Not all peripheral nerve stimulators have the capability of continuous stimulation and many have tetanus buttons that if deployed on an awake patient would cause significant pain. These traditional nerve stimulators are not designed for continuous P6 accustimulation.
Electrical stimulation of the P6 acupuncture point, in particular, has been found to reduce the incidence of postoperative nausea and vomiting (PONV). According to the Amberger et al. study (Monitoring of Neuromuscular Blockade at the P6 Acupuncture Point Reduces the Incidence of Postoperative Nausea and Vomiting; Anesthesiology, V. 107, No. 6, December 2007) antiemetic drugs generally can reduce, but they do not eliminate postoperative nausea and vomiting (PONV). Acupuncture and its different approaches, such as needle acupuncture, electroacupuncture, and acupressure, are well described in nausea treatment. This approach is non-pharmacologic and offers the same independent efficacy as does ondansetron according to the Amberger study.
As stated, the P6 or Neiguan acupuncture point is located just proximal to the distal skin crease of the wrist, or more specifically in the anterior antebrachial region on the ulnar side of the tendon of the flexor carpi radialis. It was found that stimulation of the P6 acupuncture point in adult women undergoing gynecologic laparoscopic surgery showed a marked reduction of PONV incidence. That is, transcutaneous electrical stimulation of the P6 acupuncture point reduced nausea. Thus, Amberger et al. concluded that intraoperative P6 acupuncture point stimulation with a conventional nerve stimulator during surgery significantly reduced the incidence of PONV over 24 hours. The efficacy of P6 stimulation is similar to that of commonly used antiemetic drugs in the prevention of PONV. It is possible that using both pharmacologic and non-pharmacologic modalities may be synergistic.
Various approaches to electrostimulization in general have been considered. In one approach, there is provided a disc shaped device that has two primary layers. A first layer for adhering to a patient's skin surface and a second layer on the underside of which electrical circuitry is printed or affixed so that the electrical circuitry is sandwiched between the layers. Single use and reusable devices have further been contemplated. In the reusable device a pressure-sensitive adhesive material forms the lower layer which allows for multiple applications to a patient's skin. In either configuration, metal core insulated leads can be used for electrical connection with the opposite ends of the leads connected to jacks for connection to an impulse stimulator or can end in electrically conductive tabs.
In another approach, an electro-acupuncture device including a hydrogel for enhancing electrical conduction between the device and the skin and to provide an impedance matching layer between the device and the skin is contemplated. The hydrogel masses are sized and dimensioned so that when the pad is adapted to the device, the hydrogel masses do not bridge the electrodes to cause a short between the electrodes.
Other related devices not indicated for addressing nausea have also been described. One such approach involves an electrode-battery assembly for a miniature wireless transcutaneous electrical neuro or muscular stimulation unit capable of being removably attached. The assembly is generally comprised of two sided electrodes, batteries, various conductive transmission materials and a mechanical means for securing the conductive materials to the batteries. In addition, the assembly can be rechargeable or be disposable.
In another approach, a disposable electric bandage for electrical stimulation including a device for delivery of electric current. The device will increase circulation, generating motor and sensory stimulation and peripheral nerve stimulation. The device further includes circular electrodes and a circular power source, such as a battery. The electrodes are coated with hydrogel, which readily facilitates providing a moist surface and in addition a conductive interface means between the patch and body area of a subject. It is noted that a conductive interface may also be a conductive adhesive.
Further, yet another approach involves a self-contained electronic musculoskeletal stimulation apparatus that is a battery-operated device. The device applies electronic stimulation to a human with a stimulation protocol to introduce pain relieving electronic stimulation to the body for immediate, symptomatic relief of minor, chronic and acute musculoskeletal aches and pains and mild muscle tension. A patient attaches the apparatus onto the body with electrogel pads, which function as an adhesive to hold the apparatus in place. When the treatment button is depressed, one of the indicators will blink rapidly to indicate which intensity is currently being used to treat the patient and provide the patient with the identification of the intensity being used by the patient and an indication of treatment beginning.
Prior work has indicated, however, that existing devices are providing stimulation wave forms that are largely effective but still fail to relieve nausea and vomiting in approximately 3-5% of patients. Protocols associated with the use of the nerve stimulators have also been found lacking. Accordingly, there is need to develop a compact version of an acustimulization device that can attach comfortably to the body (i.e., wrist) so that it can be worn home and then disposed. Protocols describing the use of the device with medication are needed.
The present application addresses these and other needs. In particular, Perioperative nausea and vomiting, nausea associated with chemotherapy, nausea associated with pregnancy and nausea associated with motion. The application may be used alone or as part of a treatment regime to address nausea.